Uke catches 1st form.
Nage turns inside Uke into the Kaitenage movement, giving Uke the opportunity to catch the other hand as the turn occurs.
Continuing to hold with the 2nd hand as Nage sweeps back would cause Uke to fall so Uke lets go. Nage merely carries on with the Kaitenage

Nage = Sensei Mark Eastman.
Uke = Sensei Andy Lyon.
Clip Ref=ka20